Honestly, I always found this model terrible also. To me it would imply that e.g. introverts would arrive at a social event active, cheerful, outspoken, comfortable and then as the event progressed they would gradually become quieter, less comfortable, more detached. And extroverts the other way around - would arrive tired (assuming they were alone earlier) and gain steam as the event went on.
I can't think of a single person in my life persistently matching either of those.
If anything, it seems to better model person's reaction to alcohol.
